A cascading style sheet (CSS) is a file that includes descriptors that define hypertext markup language (HTML) properties to control the aesthetics of various elements such as buttons, backgrounds, and navigation controls for an HTML document. A CSS can include variable definitions and the variables can be given desired values by an author or designer to achieve a desired aesthetic. A global variable is used throughout the document. A scoped variable is used only within a component or components of the document and is thus limited in scope. A scoped variable can also be referred to as a component variable. Changes to global variables in a CSS can be made in order to change the appearance of the document as a whole. Component variables are defined at the component level.